Photographic film



PI C. SEEL, H. COMBS AND R. KEMP.

PHOTOGRAPH() FILM.

APPLICATION FILED MAY l0, 1920.-

. Patented Mar. 8, 1921.

Paul Offeel,

INVENToRs,

wnNEssEs:

Y ATTORNEY i Lamaze.

UNITED STATES A PATENT OFFICE.l

PAUL O. sEEL, HENRY comas, AND'RIOHARD KEMP, OE ROCHESTER, NEW YORK,

ASSIGNORS 'ro EASTMAN KODAK COMPANY, or ROCHESTER, NEW YORK, A OOR- PORATION F NEW YORK.

PHOTOGRAPHIC FlLM.,

Specification of `Letters Patent.

Patented Mar. 8, Y1921.

Application led May 10, 1920. Serial No. 380,410.

' vphotographic lilm in which the nitrocellulose sheet or base contains suiiicient greasy softener, such as castor oil, to enhance the flexibility of Vsuch base without repelling the light-sensitive gelatino-silver haloid emulsion; or in other words without preventing the interunion ofA said base and emulsion through a suitable substratum layer.

iPhotograplfiic iilms are known, the bases.

o i which contain nitrocellulose and relatively non-greasy but expensive camphor.

in the nitrocellulose species of artificial leather the use has been proposed of greasy but inexpensive castor oil as a softener; but its use in photographic films has been considered to be impractical. Certain experimenters, 'for instance, have definitely stated that greasiness in a nitrocellulose film causes the latter to repel photographic emulsions,- see il.' S. Patent 610,861, Goodwin, Sept. 13, 1898, page 2, lines 122 to 125. Now sufi ficient amounts of castor oil to impart flexibility to a nitrocellulose base also undoubtedly give it adecidedly greasy type of suriace. Consequently it might logically have been expected that aA reliable union of such base with the emulsion could not be eti'ected Vf e have discovered, however, that when the castor Oil is incorporated with the nitrocellulose together with certain additional ingredients, the greasiness of the surface on the resulting sheet or film base is not harm- 'iful it a gelatino-silver haloid emulsion layer be 'united to such base by means of an intermediate substratum of the type disclosed in Ufs. Patent No. 550288, Penniman, Nov. 2e, 1895. Such a substratum contains gelatin and a nltrocellulose solvent, such as acetic ether, which is a solvent for gelatin also.

Because of the solvent this very thin intermediate layer unites with both the nitro-I cellulose and the gelatino-silver haloid emulsion by a slight ntermingling at the surfaces of such layers in a way probably analogous to a welded or soldered joint in metals.

This action we prefer to call an interunion. l

life have found that film made in this way does not frill. during the ordinary photographic fluid treatmentsgand in the case of positive motion picture film the image layer, derived from the gelatino-silver haloid emulsion layer, still adheres to the nitrocellulose base suiiicicntly to resist the bending, abrading and heating actions tov which it is subjected in the motion picture projectors.

inthe accompanying drawing the single ligure is a diagrammatic sectional viewpon an exaggerated scale of a photographic iilm embodying our invention.

In carrying out one illustration of our invention, we thoroughly incorporate in 100 parts of nitrocellulose and 30 to 100 parts ot fusel oil or butyl alcohol7 an amount of castor oil equal to from one per cent. to twenty per cent. of the weight of the cellulose ni.- tratefV The intermixture of these ingredients is accomplished by means of 400 to 600 parts of acetone or methyl alcohol or a mixture ofthese substances' in any proportion. When the ingredients are thoroughly mixed into a liomogenoussolution or flowable mass, they may be filtered if desired. The various ingredients are of the grades usually used in the nitrocellulose art. rlhe butyl alcohol may be any of the isomers included under that term'or a mixture of them, the synthetic butyl alcohol of commerce being the least expensive at the present time. The methyl alcohol is of the grade which exhibits suflicient solvent action on nitrocellulose.

The solution, being of the proper thickness and viscosity, is flowed in the well known way into sheets or'film base, the volatile constituents passing OE after the spreading of the sheet but not too rapidly tol im-l pair the product. The resulting film base 1 containing cellulose nitrate and higher aliphatic alcohols of from 4 to 5 carbon atoms, such as the fusel oil and butyl alcohol mentioned above, together with castor oil vis very flexible, transparent and uniform. It is waterproof and unafectedby ordinary photographic chemicals.

When the film `or sheet l thus formed is sufficiently dry, it is coated with a very thin layer of substratuni 3 containing gelatin and a solvent for nitrocellulose of the Penniman type. Then the gelatino-silver haloid emulsion 2 is coated over this in the customary manner. The final product has the necessary union of all the assembled layers, so that it withstands the customary photographic manipulations and usage and yet it has, the flexibility of?y its base enhanced by the relatively inexpensive but inherently greasy caster oil. In the drawing the interuniting substratum layer 3 is shown with' out ruled outlines to diagrammatically indiycate the slight intermingling of this layer prising a flowed nitrocellulose sheet contain-A ing aliphatic alcohols offrom 4: to 5 carbon atoms and sufficient castor oil to enhance the fiexibility of said sheet, (2) a light-sensitive gelatine-silver haloid photographic emulsion and '(3)' asubstratum layer intermediate said sheet and said emulsion, and firmly interuniting them, whereby separation of said emulsion from said sheet during normal pl'tographic use is prevented.

'gned at Rochester, New York, this 24th 40 day of April, 1920.`

PAUL C. SEEL.

HENRY COMBS.

RICHARD KEMP. 

